Daniel Kahneman is one of the most renowned psychologists of the twentieth century. His awards include the American Psychological Association’s Distinguished Scientist Award (1982) and Award for Lifetime Contribution to Psychology (2007), the Grawemeyer Award in Psychology, and the Nobel prize in economics in 2002. These awards were based on his work in the field of judgment and decision making, carried out with his close friend and collaborator, Amos Tversky. Their work on heuristic shortcuts in decision making is a classic of psychology. Although less widely known, Kahneman’s work related to positive psychology has also been of fundamental importance.

Daniel Kahneman’s early boyhood years were spent in a France occupied by the Nazis. After World War II, his family moved to Israel, where he received his bachelor’s from Hebrew University. He traveled to the United States to obtain his PhD from the University of California at Berkeley and then returned to Hebrew University as a professor. In 1978 Kahneman moved to the University of British Columbia, returning in 1986 to the University of California at Berkeley. Finally, he moved to the Woodrow Wilson School of policy at Princeton University in 1992, where he has spent the remainder of his career.

An area of Kahneman’s work related to positive psychology asks questions about how people recall and predict happy and unhappy moments. In his now famous peak-end experiments, Kahneman demonstrated that in recalling pleasant and unpleasant episodes, people largely neglect the duration of the episode and base their recall on the peak moment, as well as on the final moments. The counterintuitive finding was that an unpleasant addition to an event, if less unpleasant than what came before, led to the episode being recalled as less unpleasant, despite the greater duration of unpleasantness. Because people’s memories of events influence their future choices, Kahneman’s work on hedonic memories is important in understanding how people construct and recall a happy life.

Kahneman critically analyzed the economic concept of “utility” (the value a thing has for a person), parsing it into choice utility (what people select among alternatives), remembered utility (how they remember hedonic events), and predicted utility (what they predict about the pleasantness produced by choices they might make). In this way, Kahneman revealed that the choices people make, the type of utility emphasized by economists, is not the only form of well-being that is relevant to people’s behavior. In his work on predicted utility, Kahneman described the “focusing illusion,” in which people focus on a salient attribute of a choice when making hedonic predictions, and ignore most other features of the choice.

Daniel Kahneman has been a champion of aggregated pleasant moments as the core of happiness, rather than global judgments of life or recalled happiness. In his early view, pleasant moments were the fundamental building block of happiness, and recalled moments were subsidiary. For this reason, Kahneman and his collaborators developed the Daily Reconstruction Method (DRM), which aims to assess happy moments in particular activities. Kahneman subsequently adopted a hybrid model of well-being in which Life Satisfaction and Experienced Happiness are separate constituents.

In 1999 Kahneman, along with Ed Diener and Norbert Schwartz, edited a comprehensive volume on the psychology of pleasant and unpleasant experience, entitled Well-Being: The Foundations of Hedonic Psychology. Although much of Kahneman’s research has been focused on errors and biases, it is important to positive psychology because it shows how people can go wrong in building a positive life. Furthermore, judgment heuristics can lead in most cases to more efficient decision making. Kahneman’s work on the recall, experience, and prediction of momentary happiness is one of the most important programs of psychological research for understanding happiness in terms of pleasant feelings. Thus, Daniel Kahneman is one of the prominent figures in developing our understanding of happiness.